Brake for conveyor trolley



O United States Patent [1113,548,752

[72] inventor Karl R. M. Karlstrom 3,397,650 8/1968 Kondur 104/172 115840 Eleven Mile a Roseville. FOREIGN PATENTS [21] Appl- No- 808,875,. 1- 966,003 8/1964 Great Britain 104/ 1 72 [22] Filed Mar. 20, 1969 Primary Examiner-Arthur L. La Point [45] Patented Dec, 22, 1970 Assistant Examiner-Robert Saifer Continuation-impart of application Ser. No. Attorney-Barnes, Kisselle, Raisch & Choate 730,882, May 21, 1968, abandoned [54] BRAKE FOR CONVEYOR TROLLEY F1 10 claims 7 Drawing ABSTRACT: conveyor system comprising a track along which [52] US. Cl. 104/172, a plurality of carriers are movab]e Each can-i" includes a 188/53 pusher dog that is movable into and out of position for engagem 8 17/42, ment by a pusher lug of a conveyor chain. Each carrier is pro- B51h 9/00 vided with wheels and a pivoted cam brake member which is [50] Field of Search 104/172, normally urged by gravity in a direction to bring surfaces 178; 188/52 33 thereof into engagement with the wheels'to frictionally engage the wheels. When the pusher dog is in position for engagement [56] References Cited by the pusher lug of the conveyor, 3 pin on the pusher dog nor- UNITED STATES PATENTS mally holds the cam brake member out of engagement with 1,824,484 9/1931 Jackson 188/20 the wheels.

I l I I PATENTEDUEB22I97B 3548752 SHEET 1 [IF 2 r I INVENTOR. KARL R. M. KARLSTROM ATTOR NEVS tion.

BRAKE FOR CONVEYOR TROLLIEY This application is a continuation-in-part of application Ser. No. 730,882, filed May I968, 1968, now abandoned.

This invention relates to conveyor systems and particularly to power and free conveyor systems.

In power and free conveyor systems, it is common to have a plurality of carriers that are movable along a track by engagement with a conveyor chain. In order to accommodate obstacles or accumulation of the carriers, it is common to have a movable pusher dog on each carrier which is movable into and out of position for engagement with a lug' of a conveyor chain. When the pusher dog is moved out of engagement with the lug of the conveyor chain and the movement of the carrier is thus stopped on the track, it is desirable to provide a brake to prevent retrograde movement of the carrier along the track.

Among the objects of the invention are to provide a conveyor system which utilizes a simple, effective, economical brake system that is operable when the pusher dog is moved in a direction to disengage it from the lug of the conveyor chain.

In the drawings:

FIG. 1 is a partly diagrammatic side elevational view of a conveyor system embodying the invention.

FIG. 2 is a fragmentary sectional view on an enlarged scale taken along the line 2-2 in FIG. 1.

FIG. 3 is a fragmentary side elevational view on an enlarged scale of a portion of a carrier utilized in the system shown in FIG. 1, parts being broken away.

FIG. 4 is a part sectional plan view'of the carrier shown in F163.

FIG. 5 is a fragmentary sectional view taken along the'line 5-5 in FIG. 4.

FIG. 6 is a fragmentary sectional view taken along the line 6-6 in FIG. 4, showing the parts in a different operative posi- FIG. 7 is a fragmentary view similar to FIG. 6 on an enlarged scale.

Referring to FIG.' 1, a conveyor system comprises a track 10 along which a plurality of carriers 11 are moved. The system further includes a conveyor chain track 12 along which wheeled trolleys 13 are moved by a drive conveyor chain 14.

As shown in FIG. 2, the track 10 comprises inwardly facing channels 15 and the conveyor track '12 comprises an I-beam, the lower flange of which is engaged by the wheels 16 of the trolleys l3. Carrier 11 comprises a front trolley 17 and a rear trolley 18 interconnected by a pivoted tie bar 19. Each of the trolleys supports C-hooks 20 for carrying aload.

As shown in FIGS. 1 and 3, the conveyor chain 14 includes downwardly extending pusher lugs 21 which are adapted to engage a movable pusher dog 22 on the front trolley 17 of the carrier 11.

As shown in FIG. 3, pusher dog 22 is movable generally vertically within hollow body 23 of front trolley 17.'A lever 24 is pivoted intermediate its ends at 25 on body 23 and to the lower end of pusher dog 22 as at 26. The lever 24 extends forwardly and includes an upwardly and forwardly extending surface 27 that is adapted to engage a corresponding surface 28 on a rearwardly extending member 29 on the rear trolley 18 of a preceding carrier. When lever 24 engages member 29, it is pivoted clockwise as viewed in FIG. 3 bringing it to the solid line position shown in FIG. 3 and thereby moving pusher 22 out of position for engagement by the pusher lugs 21. Thus, the movement of the carrier is interrupted along the track 10.

As shown in FIG. 3, the body 23 supports longitudinally spaced pairs of wheels 30 that ride on the upper surface of the lower flanges of track members 15 and guide rollers 31 which are rotatable about vertical axes and are adapted to engage the edges of the lower flanges of channel members 15 (FIG. 2). A cam brake member 32 is pivoted on a pin 33 intermediate each pair of wheels 30 along each side of the carrier body 23. Cam brake member 32 is generally rectangular and has diametrically opposed surfaces 34 thereof cut away and curved to form braking surfaces while the opposite diametrically opposed comers 35 are intact. As shown in FIG. 7, the

center X of the pin 33 is spaced from the center of gravity C of the member 32. This unbalances or counterweights the member 32 so that it tends to be yieldingly urged in counterclockwise direction as viewed in FIGS. 5 and 7 to bring the surfaces 34 into engagement with thewheels 30. By this arrangement, in the absence of some means for holding the brake member 32 out of contact withthe wheels, the brake member 32 would contact the wheels providing a slight frictional drag when the trolley is moved in a forward direction and providing a brake preventing retrograde'movement of the trolley in the rearward direction.

However, when the pusher dog 22 is in its upper position as shown in broken lines in FIG. 3, a pin 36 extending horizontally on the pusher dog 22 has its ends extending upwardly into notches 37 in the cam brake members '32 holding the cam brake members in a position such that the surfaces 34 are out of contact with the wheels 30 (FIG. 5).

However, when the lever 24engagesthe preceding carrier or when a stop member engages a cam surface 370 on the pusher 22, the pusher dog 22 is moved downwardly moving the pin 36 out of engagement with the notches 37 of each of the cam brake members 32 permitting them to pivot and thereby bringing their surfaces 34 into engagement with the wheels to prevent any rearward movement of the carrier.

In order to insure that the cam brake members 32 will move into engagement with the wheels, even in the presence of dirt and grease, a torsion spring 38 is provided on the pin 33 and has one end thereof engaging the body 23 of the trolley and the other end thereof engaging its respective cam brake member 32 yieldingly urging it in a direction tendingto bring the surfaces 34 into engagement with the' wheels.

In accordance with conventional construction, thev trolley 17 is provided with a pivoted and counterweighted holdback dog 22a.

I claim:

1. In a conveyor system, the combination comprising:

a track;

at least one carrier movable along said track;

said carrier having at least one pair of wheels thereon;

a conveyor for driving said carrier along said track;

means on said carrier movable into and out of engagement with said conveyor;

a brake member movably mounted on said carrier and normally yieldingly urged in a direction for engagement with said wheels;

means operable when said conveyor engaging means is in engagement with said conveyorto maintain said brake member out of engagement with said wheels;

said last-mentioned means being responsive to movement of said conveyor engaging means out of engagement with said conveyor to permit said brake member to engage said wheels;

said brake member comprising a cam pivotally mounted between said wheels and having surfaces thereon adapted to engage said wheels;

said cam brake member being generally rectangular and having diametrically opposed portions thereof curved to form said wheel contacting surfaces; and

the center of said brake member being spaced'from the center of gravity of the pivot thereof to unbalance said member yieldingly urging said cam member toward said wheels.

2. The combination set forth in claim 1 including spring means supplementing the action of gravity yieldingly urging said brake member into engagement with'said wheels.

3. In a conveyor system, the combination comprising:

an overhead track;

at least one carrier including a trolley movable along said track;

said trolley having wheels thereon;

a conveyor for driving said carrier along said track;

a pusher dog on said trolley movable into and out of position for engagement with a lug on said conveyor;

a brake member movably mounted on said trolley and normally yieldingly urged in a direction for engagement with said wheels;

interengaging means between said pusher dog and said brake member operable when said pusher dog is in engagement with a lug on said conveyor to maintain said brake member out of engagement with said wheels;

said last-mentioned means being responsive to movement of said pusher dogout of engagement with a lug on said conveyor to permit said brake member to engage said wheels;

said brake member comprising a cam pivotally mounted between said wheels and having surfaces thereon adapted to engage said wheels;

said cam member being generally rectangular and having diametrically opposed portions thereof curved to form said wheel contacting surfaces; and

the center of gravity of said brake member being spaced from the center of gravity of the pivot thereof to definea counterweight yieldingly urging said cam member toward said wheels. I

4. The combination set forth in claim 3 including spring means supplementing the action of gravity yieldingly urging said brake member into engagement with said wheels.

5. For use in a conveyor system:

a trolley comp ising a body;

said trolley having wheels thereon track;

a pusher dog on said trolley movable into and out of position for engagement with a lug of a conveyor;

a brake member movably mounted on said body and normally yieldingly urged in a direction for engagement with said wheels;

interengaging means between said pusher dog and said brake member operable when said pusher dog is in engagement with 3. lug of a conveyor to maintain said brake member out of engagement with said wheels;

said last-mentioned means being responsive to movement of said pusher dog out of engagement with a lug on a conveyor to permit said brake member to engage said wheels;

said brake member comprising a cam pivotally mounted between said wheels and having surfaces thereon adapted to engage said wheels;

said cam member being generally rectangular and having diametrically opposed portions thereof curved to form said wheel contacting surfaces; and

the center of gravity of said brake member being spaced from the center of gravity of the pivot thereof to define a counterweight yieldingly urging said cam member toward said wheels.

6. The combination set forth in claim 5 including spring means supplementing the action of gravity yieldingly urging for engagement with a means on said carrier movable into and out of engagement with said conveyor;

a brake member movably mounted on said carrier;

said brake member being operable to permit movement of the carrier in a forward direction and prevent retrograde movement of the carrier in a rearward direction;

said brake member comprising a cam pivotally mounted on said carrier and having a surface movable into engagement with said wheels;

said cam brake member being adapted to contact a pair of wheels and being generally rectangular and having diametrically opposed portions thereof curved to form said wheel contacting surfaces; and

the opposite diametrically opposed corners extending radially outwardly from said pivot point to unbalance said member yieldingly urging said cam member toward said wheels. g 8. The combination setforth in claim 7 including spring means supplementing the action of gravity yieldingly urging said brake member into engagement with said wheels.

9. For use in a conveyor system: i a trolley comprising a body; said trolley having wheels thereon for engagement with a track; a pusher dog on said trolley movable into and out of position for engagement with a lug of a conveyor; a brake member movably mounted on said body; said brake member being operable to permit forward movement of the trolley and being operable to prevent retrograde movement of the trolley; v said brake member comprising a cam pivotally mounted on said carrier and having a surface movable into engagement with said wheels; said cam member being adapted to contact a pair of wheels and being generally rectangular and having diametrically opposed portions thereof curved to form said wheel contacting surfaces; and I z the center of gravity of said brake member being spaced from the center of gravity of the pivot thereof to define a counterweight yieldingly urging said cam member toward said wheels. 10. The combination set forth in claim 9'including spring means supplementing the action of gravity yieldingly urging said brake member into engagement with said wheels. 

